Conventionally, a tire for construction vehicles (dump truck and the like) operated mainly in construction sites, mines and the like, in order to improve wear resistance of the tire, typically has an increased volume of tread rubber by increasing a thickness of a tread or, alternatively, by reducing a negative ratio.
However, since the tire for the construction vehicle is used for transport works at a relatively high speed, tire failure may be caused due to heat generation in a tread portion. Such a failure has been a problem particularly for the tire having a large volume of the tread rubber as described above.
For this reason, techniques for improving the abrasion resistance of the tire without increasing the volume of the tread rubber have been actively developed (for example, see Patent Documents 1, 2).
There is also a known technique to provide a tread with a directional pattern and a lug groove in a parallelogram shape, so as to allow gradual stepping from a tread center side.
When a super-large ORR tire is mounted as a front wheel of a vehicle, because of a motion of a belt at the time of tire rolling, a shear stress is increased at a position what is called a ¼ point of the tread and the tread greatly slips at start of kicking-out. According to the above technique, however, the slip in a tread width direction may be suppressed.